Head Mounted Displays (HMDs) have been prevalent in recent years. An HMD is a display device that is mounted on a user's head and displays computer graphics (CG) video and/or remote video to the user, which provides the user with a virtual reality experience.
Since the eyes of the user wearing a whole-screen type HMD are covered with a display, it is difficult for the user wearing the HMD to operate an input device such as a keyboard and thus difficult to change a viewpoint within a video display. Thus, there is a demand for a technique that allows the user wearing an HMD to change a viewpoint within a video display by making a predetermined gesture or the like.
A first related art will be described. The first related art enables six-direction navigation by using a fixed sensor such as a Kinect (Registered Trademark) to recognize a gesture based on the motion of a user's arm. FIG. 15 is a diagram illustrating the first related art. For example, as illustrated in a gesture 1A, upon the user stopping their arm at a position, a device receives an instruction to stop motion. As illustrated in a gesture 1B, upon the user moving their arm position to the left, the device receives an instruction of a motion in the left direction and, upon the user moving their arm position to the right, the device receives an instruction of a motion in the right direction. As illustrated in a gesture 1C, upon the user moving their arm position forward, the device receives an instruction of a forward motion and, upon the user moving their arm position backward, the device receives an instruction of a backward motion. As illustrated in a gesture 1D, the user moving their arm position upward, the device receives an instruction of an upward motion, and the user moving their arm position downward, the device receives an instruction of a downward motion.
A second related art will be described. The second related art discloses a technique that determines whether or not both hands of a user are present within a capturing range of a camera of an HMD. When both hands are present within the capturing range of the camera, the viewpoint position is moved in a forward direction. FIG. 16 is a diagram illustrating the second related art. As illustrated in FIG. 16, in the second related art, upon the user moving both hands forward, both hands are displayed on a screen, and the viewpoint position is moved forward. In contrast to the first related art, since the second related art involves only determination as to whether or not both hands are present, the user wearing the HMD is able to move the viewpoint position forward.
In addition, related techniques are disclosed in Japanese Laid-open Patent Publication No. 2012-79177, Japanese Laid-open Patent Publication No. 10-177449, and Japanese Laid-open Patent Publication No. 2014-72575, for example.